Airplane propeller



Feb. 10, 1942. E. c. STEINHAUS AIRPLANE PROPELLER Filed Dec. 2, 1940Edward 6; Stel'lzham:

INVENTOR BY amyamwza.

ATTORNEYS WITNESS Patented Feb. 10, 1942 Application December 2, 1940,Serial No. 368,241

g 4 Claims. ('01. 170-172) This invention relates to airplane propellersand more particularly to those which are hollow and utilize a flow ofcompressed air'through ducts on the surface thereof.

In the conventional type of propeller, the high rate of speed at whichthe blade rotates tends to'create a vacuum or partial vacuum on itsforward or low-pressure surface and the effect of this vacuum is toexert a retarding force on the rotationof the propeller.

r Various means, such 'as ridges, fins, etc. have been utilized to breakup this vacuum but, so far as I am aware,

no one has as yet developed a device which makes use of a stream ofcompressed air which not only abolishes this vacuum but will assist themotor of the propeller as will the specific advantageous combination ofelements embodied in my invention.

Said shaft is hollow, and has ducts positioned so that air may be forcedbya compressor, not shown, therethrough and into the hollowblades Ill.

Positioned on the forward, or low-pressure surface of the blades areconvexities l6, shaped in a backwardly tapering form similar to the backThe object of this invention is to decrease the air resistance inairplane propellers.

Another object is to abolish the vacuum, which forms on the low-pressuresurface of airplane propellers.

Still another object is a means of assisting the rotation of airplanepropellers.

These and other objects may be accomplished by my invention whichembodies among its features a propeller having hollow blades, a hollowshaft for said propeller having air ducts leading to' the interior ofsaid blades, a plurality of convexities arranged on the forward orlow-pressure surface of each blade,said congexities having a taperingshape to decrease air resistance, an air outlet positioner directly infront of each convexity and consisting of astamped-up portion of thesurface of the blade, semi-circular in crosssection and directed towardthe convexity so that,

when air is forced therethrough, it will overcome any vacuum and alsowill produce a force to augment the drive of the propeller.

Other objects and features will become evident from the followingdisclosure when taken in connection with the accompanying drawing inwhich: a

Figure l is a front elevation of a hollow propeller blade including myinvention,

Figure 2 is a cross-section taken on line 2-2 of Figural, and

figure 3 is a cross-section taken on line 3-3 of Figure 2.

' Referring to the drawing in detail, my propeller consists of twohollow blades l0, each held in a socketiiby clamps' l2. ihe socket II ismade integral with hub l3 which is securely fixed in conventional manneron under forced pressure therein, a plurality of con--.

of a spoon or a' drop of oil falling through air to thus minimize airresistance. The spaces be-' tween thes'e'convexities may, if desired, beslightly concave, and the convexities are positioned so that theirsurfaces taper. down to the trailing edge of the blade. Directly infront of the convexlties are air outlets l1 stamped out of the blade,the same being semi-circular in crosssection, as shown, and positionedto direct jets of air back over the convexities. when air is forcedthrough the shaft l4 into the hollow blades, these backwardly directedjets not only obviate the formation of a vacuum on the-lowpressure sideof the blade, but exert a considerable force to cause the .blades torotate;

Therefore, it will be noted that I have produced a blade which can berotated at a greater rate of speed with the expenditure ofv lesshorsepower and in general has greater efficiency than the blades now inuse. Although a preferred embodiment is described herein I do not wishto appended claims:

What I claim is:

1. In a device of the class described, a hollow propeller blade open atone end to receive air vexities formed transversely on the low-pressureside of the said blade, the said blade having air outlet openingsforwardly of the said convexities, and means projecting from the bladefor directing the air escaping from the said openings toward the saidconvexitles.

2. In a propeller, a hollow blade open at one end for the admission ofair under forced pressure, a plurality of convex protuberances formeddrive shaft H. 5

on the blade, ,the said protuberances being tapered longitudinally andarranged transversely of the blade, the said blade having outlet aper-'tures adjacent the ends of the said protuberances, and projectionsformed on the blade partially covering the said outlet apertures andshaped to direct the air blowing outward of the apertures on to the saidprotuberances.

3. In a propeller. a hollow elongated blade open at its inner end forconnection with a passage for supplying fluid under pressure into thebladr' a plurality of transversely disposed protuberances formed on oneside of the blade, the

' said protuberances being tapered and having one end terminating at thetrailing edge of the blade, the said blade having fluid dischargeapertures in one side thereof immediately'forward of the dischargeapertures adiacent one end of each of the protuberances, a semi-circulardeflecting member formed about a portion of each aperture to direct thefluid escaping therefrom toward the protuherances, a hollow shaft havinga plurality of side outlet ducts, and a plurality of radialsocketsmounted on the shaft for connecting the blade to the shaft sothat the inner open ends of the blade register with the ducts wherebyfluid may be forced through the shaft and into the blades, anddischarged through the apertures in the blades. 7

EDWARD C. STEINHAUS.

